PB1976: SINGLE CENTER STUDY ON SARS-COV-2 INFECTION IN PATIENTS AFFECTED BY CML: VACCINATION STATUS AND BOSUTINIB THERAPY AS POSSIBLE PROTECTIVE FACTORS FOR HOSPITALIZATION.
Authors: Ivan Civettini, Laura Antolinni, Filippo Achille Brioschi, Giovanni Paolo Maria Zambrotta, Veronica Guglielmana, Carlo Gambacorti-Passerini
Journal: HemaSphere (2023)

Topic: 8. Chronic myeloid leukemia - Clinical Background: The advent of COVID-19 pandemic had a considerable impact among haematological patients, with high mortality rates. Passamonti et al. reported that patients with chronic myeloid leukemia (CML) receiving TKI seemed to have a lower risk of mortality compared to other haematological patients. These findings were not confirmed by subsequent studies where higher mortality and hospitalization rates were reported compared to the general population Aims: To evaluate mortality, hospitalization rates and possible protective factors for hospitalization in CML patients affected by COVID Methods: Consecutive CML patients treated at our institution and with a confirmed SARS-CoV-2 infection diagnosed from February 2020 to October 2022 were followed. The following variables were assessed: TKI therapy or Treatment Free Remission (TFR), vaccination status, presence of cardiovascular disease (CVD) risk factors, period of infection, severity (hospitalized/admitted to intensive care unit [ICU]) and mortality Results: Out of a total of 325 CML patients treated at our institution, we recorded 72 SARS-CoV-2 patients (22%). No deaths were recorded (0%). 27 patients (37%) had CVD risk factors. Thirty-tree patients (46%) were not vaccinated when COVID-19 was diagnosed. Of the 72 confirmed infections, 13 patients (18%; (CI) 10-28) were asymptomatic and 48 (66%; CI: 55-76) had mild symptoms. A total of 11 patients were admitted to hospital and 3 of these patients required ICU admission. All the 3 patients admitted to ICU were not vaccinated and 2 of them were not in active therapy with TKI without a DMR Twentywto patients were infected in 2020, 16 patients in 2021 and 34 in 2022 (46%); with an hospitalization rate of 27%, 25% and 3% respectively When analysing the vaccination rate among patients at different years, in 2022 there was a 85% vaccination rate, 56 % in 2021 and 0% in 2020 The risk of hospitalization was significantly reduced in multivariate analysis if patients were: vaccinated (odds ratio (OR) 0.03, p 0.001) and in therapy with bosutinib (OR 0.06, p 0.021). Age < 50 year-old was not associated with a reduction of the risk of hospitalization (OR 0.26, p 0.3) unless the analysis were restricted to unvaccinated patients (p=0.021) Summary/Conclusion: We registered an infection rate of 22% among patients affected by CML at our center. Most of them were asymptomatic or had mild symptoms with an hospitalization rate of 15%. The death rate reported in our sample, appeared to be not significantly different from the one reported for the Italian population (1.1 %) from February 2020 to April 2022. In constrast to previous studies we noticed a lack of correlation between severity of infection and age. This could be explained by the vaccination status in our sample (49% vaccination rate) compared to previous studies. When comparing different TKI therapies at the time when COVID-19 was diagnosed, patients taking Bosutinib appeared to have a reduced probability to be hospitalized compared to patients receiving other TKIs or in TFR. This represents a new results and the potential role of this drug in this setting has to be validated and confirmed in future studies. A possible explanation could reside in the inhibitory activity of Bosutinib against the cellular entry activity of SARS-CoV-2 reported in a preclinical study or in the immunomodulation exerted by bosutinib through its Lyn inhibitory activity. In conclusion, in our study we didn’t observe an excess of mortality compared to the Italian population and we identified that being vaccinated and possibly on therapy with bosutinib represent baseline characteristics associated with a reduced risk of hospitalization due to COVID-19 infectioKeywords: Infection, COVID-19, Chronic myeloid leukemia, Tyrosine kinase inhibitor